Electro-hydraulic brake



July 10, 1962 w. sussl-:BACH 3,043,405

ELECTRO-HYDRAULIC BRAKE:

Filed March 28, 1960 Fly! /2 Inventar. WALTER sussEAC/v 2, o mmfvm 3,043,405 ELECTRO-HYDRAULIC BRAKE Walter Sussehach, Olpe, Westphalia, Germany, assigner to Elektro-Mechanik-G.m.b.H., Westphalia, Germany Filed Mar. 2S, 1960, Ser. No. 18,176 Claims priority, application Germany Apr. 3, 195 v 4 Claims. (Cl. 18S-151) l The present invention relates to brakes and more in particular to electro-hydraulic brakes.

It is known in the art to provide brake for such machines as, for instance, cranes, hoists, conveyers and the like which are equipped with 'a brake-lifting device for lifting the brakes, whereupon the brakes are returned to their initial position by spring or weight means. The brake-lifting device is connected with the brake shoes by a lever arrangement and the lifting device is disposed laterally of the brake disk.

More recently electro-hydraulic devices have proved to be of particular advantage for use as brake-lifting apparatus. In particular, electro-hydraulic apparatus known under the name of Eldro and described, for example, in Patent 2,631,431, have a number of considerable advantages. They operate smoothly and quickly, are unsensitive to great voltage drops and make it possible to use even small portions of the full stroke, thereby reducing the power consumption of the motor, particularly as soon as the piston comes to a standstill.

It is the object of the present invention to provide brake means making use of electro-hydraulic brake-lifting devices and combine them with a complete brake arrangement in such a manner that a complete and compact unit is obtained.

Further objects and advantages of the invention will become apparent as the description thereof proceeds.

The objects are achieved by the electro-hydraulic brake of the present invention according to which the brake frame is so constructed that it is simultaneously used as thepressure liquid container. The brake levers are moved by hydraulically operated members, such as particularly rotary wings, which are preferably positioned in the frame structure and within the liquid container. The motor pump unit of the apparatus can be either laterally attached to the liquid container or provided within the same. IFurthermore, the rotary wings displacing the brake levers can be mounted either directly on the brake lever shaft or on a shaft connected with the brake lever shaft by transmission means.

As a pump itis possible to use hydrostatic pump means of the twoastage type of different capacities, that is, having a greater pump and a smaller pump, with the greater pump being switched off by contact means or at f a predetermined pressure as soon as the rotary wings have reached their end positions.

The pressure liquid container is preferably positioned between the pair of brake levers, so as to obtain a compact unit. Both the pump unit and the motor can be provided with a ventilator for cooling the same.

The invention will be more fully appreciated upon the following description of the accompanying drawings, wherein- FIGURE 1 is a side elevational View of the electrohydraulic brake according to the invention;

FIGURE 2 is a plan view of the electro-hydraulic brake according to the invention;

FIGURE 3 is a fragmentary, side elevational view, partly in section, of the embodiment of FIGURE l, illustrating the motor-pump unit as closely attached to the brake frame;

FIGURE 4 is a fragmentary, side elevational view, partly in section, of another embodiment of the electrohydraulic brake of the invention, illustrating the motorfis 2 pump unit as built into the structure of the brake frame;

FIGURE 5 is a fragmentary, side elevational view, i1- lustrating transmission means for speeding up the rotary wing means relative to the brake lever shaft in the electrohydraulic ybrake according to the invention;

FIGURE 6 is a fragmentary, side elevational view, illustrating contact means for switching oif the greater pump in the electro-hydraulic brake of the invention.

The stationary brake frame `10 is constructed as a pressure liquid container and supports the two rotary wings y11, which latter are each connected with a shaft 17 supporting the brake levers 12 and `131, respectively. On the brake levers 12 and '13 are mounted the brake shoes 15. Each one of the levers `12 and 13 constitutes a unitary structure together with a rotary wing )11 and a shaft 17, the latters being rotatably mounted 4in frame 10 (see FIG. 2). An upper bar 16 connects the brake levers 12 and 13 at their upper ends, and bears a return spring 16a, for returning the brake levers and brake shoes into their initial positions after having been actuated by rotary wings y11. Resilient stop members 26 (whereof only one 'has been shown for the sake of simplicity) can be provided at the frame y10, in order to limit the movement of brake levers 112 and 13'.

According to the invention the motor pump unit 14 also forms part of the frame structure or, as shown in FIGURE -1, is closely connected therewith. This unit 14- cornprises the pump unit `18 with a pump 19 and pump 20, pump 19 having a greater capacity than pump 20. A pressure-operated valve 21 is connected wit-h pumps 19 and 20. Unit 14 further comprises a motor 22, e.g. an electric motor, and an exterior ventilator 23 with cooling ribs so as to provide a better cooling of pump unit '18. A pipe conduit 24 connects the pumps with the rotary wings "11 so as to supply pressure liquid to the latter. Upon pumping of fluid, the rotary wings are driven thereby and the torque produced becomes effective in the brake levers \12 and 13y to release the brake. The frame 10 simultaneously constituting the pressure liquid container has leakage openings 2S for removing leakage liquid.

As will be seen from FIGURE 2, the pressure liquid container is constructed small enough to tit in between the pair of brake levers 12, 13.

Whereas in the embodiment of FIGURES 1 to 3 the motor-pump unit is adjacent the brake frame and connected therewith, for example, by its flange 27 to ange 2S of the brake fra-me 10, as shown in FIGURE 3, it is also possible, according to another embodiment, to have the motor unit built into the structure of the brake frame. This is illustrated in FIGURE 4, wherein pump unit 13 and motor 22 are Amounted against cover plate 29 Iwhich latter is detachably mounted on the brake frame. The motor-pump unit is thus built into the frame structure of brake frame 10, and can be removed therefrom together with cover plate 29. Numeral 30 designates the level of pressure liquid in the brake frame 10, simultaneously constituting the pressure liquid container.

In operation, motor 22 drives pumps 19, 20, which convey pressure liquid through pipe conduit, so as to actuate rotary'wings 11, which then operate the brake levers 12, `113, and thereby brake shoes 15. The movement ofthe brake levers is limited by stop members 26, and the brake levers are returned to their initial positions by return spring 16a. As soon as the end position of the rotary wings r11 'has been reached, valve 21 causes the liquid conveyed by the greater pump to circulate without pressure, thereby greatly reducing the loa-d on motor 22 and thus economizing on power consumption.

Whereas in FIGURES l and 2 the pump unit 13 is to be understood as comprising a two-stage pump system with geared pump means or vane-type pump means, it

. pressures.

brakes needed, a pressure of not more than 8 atmospheres l Spaarne is, of course, possible to use other, conventional hydrodynamic pumps, selected -in a known manner according to the desired pressure values.

It will also be'of advantage to provide transmission Vmeans between the brake -lever shaft 17 and thefrotary wings `so as to speed -up the movement of the latter; this will make it possible to operate at greatly reduced pressure.

l Such transmission means may be of'the general type, schematically illustrated in FIGURE 5; a gear 32 is connected with rotary wing l11 and meshes with gear segment 33 mounted on the brake lever shaft 17, supporting brake'lever y13 with brake shoe `15. The gears are so 'dimensioned that the movement of rotary wing 11 is "speeded up relative to brake lever shaft 17, thus making it possible to operate at far lower pressure.

y A modification ofthe means for Switching' off the greater pump as soon as the rotary wing means have .reached their end positions, is shown in FIGURE 6. In-

stead Vofpressure-dependent valve 4means 21 it is possible to provide contact means 34as shown in FIGURE 6, for switching off pump A19, aspsoon as the rotary wing v.means 11 have reached end position.

The electro-hydraulically operated brake of the present .invention offers considerable advantages over the art.

Due to the fact that the brake frame is used as the'pressure liquid container in the lifting unit, supporting two rotary wings operating the `brake levers, and due to the fact that the motor pump unit is either closely attached to the frame .or is provided within the same, a comparatively great cooling surface is obtained while, at the same time, the overall size of the entire brake structure is .comparatively small. The brake shoes and the return spring means (16a) are easily accessible. Due to the small angular movement of the rotary wings which are in the order of less than 1/2, the braking and lifting periods are extremely small. The fact thatv the `rotary wings are mounted directly on the brakev lever shaft and particularly .the fact that transmission means can be provided speeding up the movement of the rotary Wings makes-it possible to operate vat comparatively low .It Vhas been found that even for the greatest is sufficient. By making the liquid container so small as #tot inbetween the pair of brake levers a .compact unit Y.is obtained.

It will be understood that this invention is susceptible to modiiicat-ion in order to adapt it to different usages-y a age means including said shaft means for positively interconnecting said rotary wing means and said brake levers for torque conversion and trans-mission, hydrostatic pump means with a first and a second pump thereof, said first pump has a greater conveying capacity than said second pump, and means for switching off said first pump as soon as said rotary rwing means engages said .wall

means.

2. Electro-hydraulic brake with Va brakeframe structure including a liquid `storage container, constituting a support base for the brake, a pair of brake levers having brake shoes operated above saidcontaiuer, hydraulically operated rotary wing means disposed and supported in said liquid container, shafts supported in said container and supporting said brake levers, a firsttransmission gear mounted on one of said shafts, and a second transmission gear mounted on said rotary ywing meaus'meshing with said first gear, said iirst and second gear constituting a transmission :means for decreasing the ,rotary speed vof said lever relative to the rotary speed of said rotary wing means.

3. Electro-hydraulic brake with a brake frame structure including a liquid storage container constituting a support base for the brake, a pair of brake levers having brake shoes operating above said container, shaft means for pivotally supporting said levers at said container, wall means in said container constituting apart thereof, hydraulically operating rotary wing means disposed yin said liquid container near said wall means, mechanical linkage -means including said shaft means for positively interconnecting said rotary wing means and said brake levers for torque conversion and transmission, hydrostatic pump means with a first and a second pump thereof said first pump has a greater conveying capacity than said second pump, and pressure-dependent valve means for switching olf said iirst pump as soon as said rotary wing means engages said Iwall means in said container.

4. Electro-hydraulic brake with a brake frame structure including a liquid storage container, constituting-a support base for the brake, a pair. of brake levers pivotally supported at said container and having brake shoes operating above said container, hydraulically operated rotary wing means disposed in said liquid container, mechanical linkage means for positively interconnectingjsaid rotary wing vmeans and said` brake levers for torque conversion and transmission, hydrostatic pump means with a iirst and a second pump thereof, said iirst pump has a greater conveying capacity than said -second pump, and` contact means for-switching olf said iirst pump when. said rotary wing engages said contact switching means.

AReferences Cited in the iile of this patent UNITED STATES PATENTS,

906,344 Williams et al. Dec. 8, 1908 1,637,025 McCormick July 26, 1927 1,778,317 Goldman Oct. 14, 1930 1,993,612 Lum Mar. 5, .1935 2,328,619 Cox Sept. 7, 19.43 2,612,241 Powell Sept. 30, '1952 

